Equity and Accumulated Other Comprehensive Loss, Net (Noncontrolling Interests in Operating Partnership) (Details) $ in Millions	Sep. 30, 2018 USD ($) shares	Dec. 31, 2017 USD ($) shares
Class of Stock [Line Items]
Number of units (units)	206,267,055	205,470,300
Percentage of total	96.10%	96.00%
Common stock conversion ratio	1
Common units held by third parties
Class of Stock [Line Items]
Common units held by third parties (units)	6,411,484	6,899,094
Percentage of total	3.00%	3.20%
Incentive units held by employees and directors (see Note 14)
Class of Stock [Line Items]
Incentive units held by employees and directors (units)	1,929,103	1,590,001
Percentage of total	0.90%	0.80%
Noncontrolling Interests in Operating Partnership
Class of Stock [Line Items]
Number of units (units)	214,607,642	213,959,395
Percentage of total	100.00%	100.00%
Digital Realty Trust, L.P.
Class of Stock [Line Items]
Common stock conversion ratio	1
Redeemable noncontrolling interests – operating partnership | $	$ 891.0	$ 887.0